Black dye and process of making same.



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RENE BOHN, OF MANNHEIM, GERMANY, ASSTGNOR TO THE BADISCHE ANILIN AND SODA FABRIK, OF LUDW'IGSI-IAFEN, GERMANY.

BLACK DYE AND PROCESS OF MAKING SAME.

SPECIFICATION formingpart of Letters Patent No. 661,438, dated November 6, 1900.

Application filed June 29, 1900.

To all whom it may concern:

Be it known that I, RENE BOHN, a doctor of philosophy, and a citizen of the Swiss Republic, residingat Mannheim,in the Grand Duchy of Baden, Germany, have invented new and useful Improvements in Black Coloring-Matter, of which the following is a specification.

My invention relates to the production of a new black coloring-matter from 1.8 dinitro naphthalene. The said new coloring-matter is obtained by treating at a high temperature a solution of 1.8 dinitro-naphthalene in concentrated sulfuric acid with a sulfid, preferably hydrogen sulfid. It appears thata naphthazarin intermediate product is formed during this treatment and that thisis converted into the new coloring-matter. Thenew coloring-matter reacts with bisulfites orsulfites and is converted into a more soluble form. It is, especially in this more soluble form, excellent-ly adapted for use in printing cotton goods, the printing being effected by the addition of a metallic mordant-for instance, chromium acetate. Gray to deep-black lakes can thus be obtained on the fiber, and these are characterized by a high degree of beauty and fastness, so that in this respect the new color is equal or superior to that obtained with naphthazarin. Further, the price at which my new coloringqnatter can be produced is so low that it replaces logwood by a coal tar product in a way that has not hitherto been attained.

The following examples will serve to further illustrate my invention and the manner in which it can be carried into practical effect and my new coloring-matter obtained. The parts are by weight.

Example 1: Mix about one hundred (100) parts of 1.8 dinitro-naphthalene in an iron vessel with from one thousand (1,000) to two thousand (2,000) parts of sulfuric acid, (containing about ninety-six per cent. H 80 Heat the mixture to about 130 centigrade. \Vhen solution is practically complete, pass in a stream of hydrogen sulfid (sulfureted hydrogen) while continually stirring the mixture. The solution, which is at first yellow, during this treatment turns red, and if test portions be taken and poured into water a blue-black body separates out, Which disierial No. 22,063. (Specimens) solves in caustic soda, the solution being blue. Continue the treatment with hydrogen sulfid until tests that are made from time to time show that practically no dinitro-naphthaleue remains unchanged. in about from six to eight hours. Allow the melt to cool, pour it into five hundred (500) parts of water, boil, allow to cool, filter, and wash the product remaining on the filter. The product thus obtained has some naphthazarin mixed with it. I have found that this can be removed, if desired, by extracting by means of a solution of alum.

The coloring-matter so obtained can either be used directly or it can be converted into the form of its soluble bisulfite compound (which is especially suited for printing cotton goods) in the manner hereinafter described in Example 3.

Example 2: Mix about one hundred (100) parts ot'1.8 dinitro-naphthalene and one thousand (1,000) to two thousand (2,000) parts of sulfuric acid (containing about ninety-six per cent. H 80 and heat the mixture to about 130 centigrade. To the solution add gradually about sixty parts of antimony sulfid. A vigorous reaction takes place, and the solution, which was originally yellow, turns red. Work up in the manner described in the foregoing Example 1. The product so obtained also contains naphthazarin. It desired, the production of naphthazarin in admixture with the new coloringmatter can be prevented by continuing the treatment with hydrogen sulfid or antimony sulfid, as hereinbefore described, until test portions of the melt on pouring into water yield a product insoluble in water--that is, containing no admixed soluble product. The product obtained after this prolonged treatment with the sulfid is less suited for dyeing wool.

Example 3. To obtain the soluble bisulfite compound of the new coloring-matter, take about two hundred (200) parts of a paste of the new coloring-matter containing tweutyfive per cent. of the new dye and mix them with seventy-five parts of sodium bisulfite con taining about forty per cent. real bisulfite NaHSO Heat the mixture for from about oentigrade.

This is usually the case,

be brought to a standard strength by the addition of water. It is completely soluble in boiling water and can be used for'printing cotton goods, as hereinbefore mentioned.

My new coloring-matter in the insoluble form is a dark powder with a metallic luster which is preferably used in dyeing in the form of paste. in cold water, rather more soluble in boiling It is but very slightly soluble water, giving a dirty-blue violet soiution. v The solution in concentrated sulfuric acid as I also in fuming sulfuric acid (containing twenty-three per cent. free an hydrid) is dirty red-violet in color.

In the 'form of its soluble bisulfite com pound my new coloring-matter is soluble in water, givinga yellow-brown solution. In sodium-carbonate solution the color is brown, changing slowly upon contact with air. The solution in caustic soda is also a brown color,

which soon turns dirty-blue. In concentrated 1 -sulfuric acid the solution is dirty brown in j dinitro-naphthalene with concentrated sulfuric acidand a sulfid at .a high temperature, substantially as described. I

3. As a new article of manufacture the new black coloring-matter which can be obtained by treating 1.8 dinitro-naphthalene with concentrated sulfuric acid and hydrogen sulfid, and which is nearly insoluble in cold water, slightly soluble in boiling water giving a dirtyblue-Violet solution, and which is soluble in concentrated and in fuming sulfuric acid (containing twenty-three per cent. S0 giving in both cases a dirty-red-violet solution,

1 all substantially as described.

4. The herein-described dye which can be derived from dinitronaphthalene, concentrated sulfuric acid and hydrogen suliid, and which is soluble in cold water giving a yellow-brown solution,soluble in carbonate-of-so dium solution giving a brown solution which changes very slowlyvin the presence of air; soluble in-caustic-soda solution with a brown color which soon changes to dirty blue, and which gives a dirty-brown solution in concentrated sulfuric acid, all substantially as described.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

RENE BOIIN. Witnesses:

ERNEST E. EHRHARDT, EERNHARD O. HESSE. 

